Dental tool holder



Apl 21, 1925.

W. L. THIEDEMANN DENTAL TOOL HOLDER Filed Dec. 1 5,` 1921 Patented Apr.2l, 1925:.

UNITED STATES 1,534,816 PATENT OFFICE.

WILLIAM L. THIEDEMANN, OFMUSKEGON, MIQHIGAN, ASSIG'NOR T0 THIEDEMANN-HARDY COMPANY, F MUSKEGON, MICHIGAN, A COPARTNERSHIP COMPRISING WILLIAML. THIEDEMANN AND HAZLETT M. HARDY.

DENTAL TOOL HOLDER.

Application led December 15, 1921.

object to provide a device which is simple.

in construction, eiiicient in operation and easily cleaned.

These handpieces are used to hold and operate a rotary tool which isinserted in the mouth of the patient, and it is particularly importantthat the construction may be quickly and easily disassembled for thepurpose of sterilization and cleaning. It is -impracticable to attemptto sterilize Vthe assembled handpiece as this tends to solidify ordestroy the lubrication and produces rust without removing the grit.lThe assembled liandpiece cannot be adequately lubricated without usingan excess of oil which subsequently will be released in the patientsmouth. In order to eliminate these objectionable features a constructionhas been devised which will permit practically the entire liandpiece tobe almost instantly disassembled, or assembled, without the use of anytools. The individual parts may then be thoroughly sterilized, cleanedvand given a thin coating of oil prior to assembling.

Further important features of the invention are to eliminate jointswhich may become loose during` the operation of the device, to providean improved holder to receive the bur or other operating tool, tofacilitate the connection of the haiidpiece with .the driving shaft, andin general to provide a new and improved handpiece for the purposedescribed.

The many other objects and advantages of the invention will be betterunderstood by reference to the following specification when consideredin connection with the ac# companying drawing illustrating a selectedembodiment thereof, in which:-

Fig. 1 is a central longitudinal section of a type of handpieceembodying my invention.

Fig. 2 is a top plan view of the outer end Serial No. 522,486.

portion of the handpiece showing the parts in the Fig. 3 is the saine asFg.2,rshowing the toollocked in operative position, and

Fig. 4 is an elevation of one type of operating tool. f

Referring to the drawings, the handpiece 5 is adapted to be secured uponthe end of the flexible driving cable by the usual spring connection(not shown) which is provided at its end with a threaded ferrule toreceive the shank 6 on the inner end of the sleeve 7 ofthe handpiece.The inner end of the driving shaft 8 is threaded to receive a dog 9which is provided with a spur 10 to form an interlocking connection withthe outer end ofthe main driving shaft.

A slip joint sleeve 11 is splined upon the sleeve 7 and is provided withthe usual spring latch 12 which engages a notch 13 in the sheath 14 ofthe handpiece. A forwardly projecting pin 15 on the sleeve 11 is adaptedto enter a` slot 16 in the sheath 14 to prevent relative rotation ofthese parts when in their assembled position. The forward end of theshaft 8 is longitudinally slidable within a sleeve 17 and is providedwith a laterally projecting lug 18 which enters the slot 19 in thissleeve, in order that the rotation of the shaft shall cause acorresponding rotation of this sleeve. The end portion of the shaft 8 islongitudinally slotted at 20 and a serrated cani face 21 is formed on aweb connecting the walls of this slot. The ciain face 21 is engaged bythe inner end of the cani lever 22 which has its opposite end pivotallyconnected to the sleeve 17 at 23. This cam lever 22 is provided with anop` erating nose 24 which engaes the head of a plunger 25 seated in aplunger block 26 longitudinally slidable within the sleeve 17. Theforward end of the plunger block 26 is provided with a conical recess 27which fits the correspondingly shaped end of the double end chuck 28.The forward end 8O of the sleeve 17 is contracted to forin a conicalrecess 31 similar to the rece-ss 27 only reversed in position, so thatwhen the plunger is forced outwardly by the lever 22 both ends of thechuck 'are tightly coinpressed upon the shaft 29 and this shaft islocked to the sleeve 17. .The chuck 28 is divided longitudinally topermit thi-s com pression. The inner end of the shaft 29 is position toreceivethe operating tool.`

preferably. extended within the plunger block 26l in` order to provide along bearing for the shaft and thus insure accurate driving action.

A tool holder 32 fits over the forward end of the sheath lil and isprevented from rotation relative thereto by the pin which enters theslot 34 in the tool holder 32. n bit-locking device 35 is secured luponthe tool holder' 32 by the stud` screwy T his bit-locking deviceconsists of a thin plate of spring metal which is providedwith a4 longithe removal of the screw.

tudinal slot 3? through which the screw passes. The inner end.v portion8S of the slot 37 is preferably" enlarged to permit the plate toberemoved from the tool holder without A pin, 39 projects laterally fromthe o uter end portion of the sheath le to enter a perforation e in. theinner portion of the plate 35 and forms` a locking engagement betweenvthe tool holder 3 2 and the sheath when the pin is within` theperforation, as shown in Fig. 3. rllhe plate 35 is provided near itsouter end with arcuate slots Ll1 and The slot 41 is adapted to receivethe upper end of the operating tool to, retain this tool vithin theholder. The; walls Vof the slot enter tht` grooves-4t in the` tool. rlheslot ft2 is adapted` to receive. a small stud screw etion the outer endof the tool holder to firmly position; the outer end portion of thevplate A small stud 46 is provided in the plate to enter a slightdepression 47 in the face of thel tool holder.

rlhe outer end of theshaft 29 is provided with a star-wheel 48 which isadapted to mesh with a corresponding gear Li9 formed on the spindlesleeveO. The spindle sleeve 50 extends through the passage 5l in theouter end of the tool holder and is provided with positioningv collarsand The collar 52 forms a `shoulder which acts against thecorresponding` shoulder e produced by the contraction ofthe lowerportion of the passage 5l. The collar fits within the noi-mal bore ofthe passage to support the upper end of the sleeve. The sleeve 50 isretained within the passage 5l b v the plate iwhen this plate is in itslatched position, as indicated in Fig. 3. The operating tool i3 passesthrough this sleeve and is prevented from relative rotation therein bythe formation of the upper portion of the tool socket which engages thecutaway portion of the tool in the usual manner.

To permit a tool to be inserted into the handpiece, the plate 35 formingthe bit-loching device is brought into the position indicated in Fig. 2.The tool is then inserted iiitothe mouth of thespindle socket in theusual manner and pressed inwardly until the shoulder formed by thecutaway portion of the tool engages the contracted upper end of thesocket, as indicated in Fig.V l.

The plate 35 is then swung upon the sci-ew 36v a pivot into the positionindicated in Fig. 3, the inner end of the plate being lifted to permitit to pass over thev pin $39, and then released when the pin is inregist ration with the perforation 40. The tool is removed fromv theholder by lifting the inner end portion of the plate 35 to release thepin and then swinging' it into the position indicated in Fig. 2.

The rotation of the tool is started by drawing the sleeve 7' outwardlj,vfroml the sheath` la which is permitted by the splined connection ofthis sleeve with the slip joint sleeve ll. This movement causes theinner end of the lever 22 to be forced outwardly by thecain face2'land'tothus force the nose 2l against the head of the plunger The plungeracts against the doublev end clutch 38 to frictionally bind the shaft tothe sleeve 17 and thus causes this shaft to be rotated by the shaft 8.Tie rotation of the shaft29 causes the sleeve 50 and the tool #la to becorrespondingly rotated. To stop the operation of the tool, the sleevei' is merely pressed forwardly into the sheath. rl`his movement of thesleeve carries the cam face 2l forwardly and releases the pressure ofthe lever 22 on the plunger 25. rlhe spring clutch` 28 now expands andreleases the shaft 29.

Assuming that the handpiece is assembled and connected in the mannerillustrated iu l, the parts are disassembled in the following manner:

The tool is removed by releasing` the plate in the manner previouslydescribed. The latch l2 is then disconnected from the notch il in thesheath ld and the sleeve 7 withdrawn. rThe withd'awal of the sleeve 'icarries with it the sleeve l? and the parts contained therein. rllhedisengagement of the plate with the pin 3Q perinits the tool holder 32to be withdrawn by a straight longitudinal movement. rlhe withdrawal ofthe tool holder releases the shaft 2S) and permits this shaft to bewithdrawn from the forward end of the sheath. The sleeve may next bewithdrawn from the tool holder by merely inif'ertino; the angle piecefrom the position indicated in Fig. l and tapping it lightly if thissleeve does not drop ein without assistance. Further disassenibliiigr ofthe partswill not usually be necessary. rlhe assembling operation isequally simple and` merely the converse of disassemblingr.

When the parts have been disassembled in the manner described, they areeasil)v sterilized and all grit and foreign matter removed therefrom.Before reassembling` the haiidpiece, the parts should be given a lightcoating4 of oil, which thoroughly lubricates the operating parts andprevents rustingr.

(lne of the very benelicial features of my vconstruction is the form ofjoint between the tool holder and the sheath. It has usually beencustomary to provide a simple threaded oint between these parts. kInview of the fact that the operator very frequently exerts pressure onthe handpiece at an angle to the axis of the tool, this form cf threadedjoint permits rotation of the tool holder on the sheath. This isexceedingly annoying. If the tool holder is screwed sufficiently tightlyupon the sheath to prevent accidental rotation, it is exceedinglydiiiicult to remove it. Frequently tools must be used to accomplish thisremoval, and this involves delay in addition to damaging the finish onthe holder and sheath.

From theforegoing description it will be readily evident that I haveproduced a dental opera-ting piece which is exceedingly simple inconstruction, easily assembled and disassembled, and convenient andefficient in operation.

I am aware that many changes may be made in the construction andarrangement of the Various parts without departing from the spirit of myinvention, and I reserve the right to make all such -as fairly fallwithin the scope of the following claims.

I claim as my invention:

1. In a dental handpiece, a tool holder provided with a socket toreceive a, tool, and means for locking said tool within said socketcomprising a latch plate provided with an open ended slot to admit andinterlock with said tool, and fasteners on said holder adapted to engagesaid plate on opposite sides of said slot when said plate is in lockedposition.

2. In a dental handpiece, a tool holder provided with a socket toreceive a tool, and means for locking said tool within said socketcomprising a latch plate pivotally mounted on the rear face of saidholder, an arcuate slot in said plate communicating with one edgethereof to receive and engage the projecting end of said tool, a secondarcuate slot in said plate on the opposite side of the first slot fromthe pivotal connection, and a headed screw projecting from said rearface and adapted to enter said second slot when said plate is in latchedposition to firmly position said plate on said holder.

3. In a dental handpiece, a tool holder provided with a socket toreceive a tool, and means for locking said tool within said socketcomprising a latch plate pivotally mounted .on a headed Screw O11 therear face of said holder and detachable therefrom without removing saidscrew, an arcuate slot in said plate communicating with one edgethereofl to receive and engage the projecting rear end of said tool, asecond arcuate slot in said plate disposed on the opposite side of thefirst slot from the pivotal connection, and a second headed screwprojecting from said rear face and adapted to enter said second slottofirmly hold said plate on said holder when said plate is moved intolatched position.

4. A dental tool holder comprising an angle piece having a transversesocket formed in the outer end portion thereof, a tool operating sleeveinsertible into said socket from the rear end thereof, a shoulder onsaid sleeve co-acting with a corresponding shoul der in said socket todetermine the advance of said sleeve within said socket, and a latchplate slidable into position to retain said sleeve within said socketand a tool within said sleeve.

5. A dental operating piece comprising a handpiece, a driving spindlerevolubly mounted in said handpiece, an angle piece slidable over theouter end of said handpiece, a transverse socket in said angle piece 7 Adental operating piece comprising a' substantially tubular casing, atransverse socket in said casing near the outer end thereof, a toolholding member revoluble within said socket, and a latch for retainingsaid member in said socket and a tool in said member. y

8. A dental operating piece comprising a substantially tubular casinghaving a transverse socket near its outer end, a tool operating sleeveinsertable into said socket from the rear end thereof, and a latch forretaining said sleeve in said socket and a tool in said sleeve,

WILLIAM L- THIEDEMANN.

